i dont have any data to post up cause i couldnt get the lc-1 and lm-1 to log at the same time in RR....but if you google search for "wideband differences in exhaust location" or something to that effect you will find some results.
I found some pretty graphs before that had 3 widebands at varying distances in the exhaust (close, middle, tailpipe) and it was progressively leaner the further it got. It was posted up by a domestic shop because they were constantly getting grief for tuning cars "so lean" at the tail pipe so they did it to prove that it wasnt any different that what the home tuners were doing in the middle of the exhaust.
And if you go back through ppb and look at Jorge's plots from P&L you will see he posts up 12:1 AFR plots constantly.....sensor in the tailpipe.